The invention relates to high frequency communication antennas, and in particular to a portable, field erectable antenna that requires only a small land area to deploy.
These tactically deployable antennas can be used to advantage in both military and commercial applications. In addition to the semi-mobile use for advanced bases and deployed personnel antennas of this type can be used at permanent broadcasting stations and military bases. In general the specification for antennas of this type call for horizontal polarization, E-plane omnidirectional patterns, guaranteed nulls in the zenith direction to reduce multipath and physical dimensions that limit the structure to less than 150 feet in height and minimum ground area.
The state-of-the-art approach to providing such an antenna has centered on a stack or turnstyle of crossed dipoles mounted horizontally over the earth. Such a system of wires has conformation like a log-periodic antenna with higher frequency band dipole near the earth and lower frequency dipole highest above ground. The main difficulty with this type of antenna is the very large ground area needed to deploy the antenna. Also the height gain of the antenna in the 7-30 MHz region is low and the null at the higher frequencies (2-5 MHz) is hard to maintain at zenith.
Accordingly, there currently exists the need for an antenna that meets the above enumerated electrical specifications and that is structurally easy to manipulate and takes up minimum ground space. The present invention is directed toward providing an antenna that achieves that end and that further provides other improved electrical and structural characteristics.